<style>
.zhezhao{ width: 100%; height: 100%; background: #000;position: fixed;  min-width: 320px;filter:alpha(opacity=50); opacity:0.5; z-index: 1000; left: 0; top: 0;}
.alert-show{ position: fixed;  width: 600px; left: 25%; margin-left:-150px; top: 50%; margin-top: -300px; z-index: 1001;}
.alert-show img{ width: 100%; height: 100%; display: block;}
.alert-show-close{ background: url("http://s.juancdn.com/jpwebapp/images/alert-close.png") no-repeat; width: 40px; height: 40px; display: block; background-size:100%; position: absolute; right: 30px; top: 5.5%;}
</style>
<div class="alert-show" id="alert-box" style="display:none">
	<a href="javascript:;" class="alert-show-close" id="close"></a>
	<a href="http://s.click.taobao.com/mr1RHPx" target="_black"><img src="/static/images/1111brand.png" width="100%" height="100%"></a>
</div>
<div class="zhezhao" id="zhezhao" style="display:none"></div>
<script type="text/javascript">
$(document).ready(function(){  
        if(getck("showalert") == "")
        {
            var data = new Date();
            var timestr = data.getFullYear() + "-" + (Number

(data.getMonth())+1) + "-" + data.getDate() + " " + data.getHours

() + ":" + data.getMinutes() + ":" + data.getSeconds();
            document.cookie="showalert=" + timestr;
        }
        else
        {
            var date_ = convertdate(getck("showalert"));
            var data = new Date();
            var num = Number(data.getTime()) - Number

(date_.getTime());
            if(num >= 1*3600000)//已经过期重新设置
            {
               document.cookie="showalert=";
            }
        }
        $("#close").click(function(){ 
		document.cookie="isshowalert=true";
		$("#alert-box").hide();
		$("#zhezhao").hide();
	});
        $("#alert-box").click(function(){ 
            document.cookie="isshowalert=true";
            $("#alert-box").hide();
			$("#zhezhao").hide();
        });
	showalert();
        //setTimeout("showalert()",1000);  //这里修改打开网页多久

之后显示提示
});

    function showalert()
    { 
       if(getck("isshowalert")  == "true")
       {
         return;
       }
       else
       {
			$("#zhezhao").show();
            $("#alert-box").show(400);
       }
    }

    var acookie=document.cookie.split("; ");
    function getck(sname)
    {
       //获取单个cookies
        for(var i=0;i<acookie.length;i++){
        var arr=acookie[i].split("=");
        if(sname==arr[0]){
        if(arr.length>1)
        return unescape(arr[1]);
        else
        return "";
        }}
        return "";
    }

    function convertdate(datestr)
    {
      var date_hidden = datestr;
      date_hidden = date_hidden.replace(":","-");
      date_hidden = date_hidden.replace(":","-");
      date_hidden = date_hidden.replace(" ","-");
      var date = new Date(Number(date_hidden.split("-")

[0]),Number(date_hidden.split("-")[1])-1,Number(date_hidden.split

("-")[2]),Number(date_hidden.split("-")[3]),Number

(date_hidden.split("-")[4]),Number(date_hidden.split("-")[5]));
      return date;  
    }

    function clearcookie()
    {
        document.cookie="showalert=";
        

document.cookie="isshowalert=";location.href=location.href;
    }   
</script>